Sensor Attachment for Three Dimensional Mapping Display Systems for Diagnostic Ultrasound Machines

ABSTRACT

A sensor attachment for use with three dimensional ultrasound mapping devices is presented. According to the invention, one or more sensors are attached to specific locations on the body, such as the nipple and sternum, the inventive sensor attachments enabling accurate recording of target information, including location and size; the present invention especially helpful in subsequent and comparative examinations. A method of use is also presented.

1. TECHNICAL FIELD

The present invention relates to diagnostic ultrasound technology and,more particularly, to a sensor attachment apparatus for use in threedimensional mapping display (“TDMD”) diagnostic ultrasound systems.

II. BACKGROUND OF THE INVENTION

Ultrasound is an important imaging modality for medical diagnosticpurposes and as a guidance tool for diagnostic or therapeuticprocedures, like soft tissue needle biopsy, tumor ablation, etc.Ultrasound can be used over the entire human body and has certainadvantages over other modalities, including, among others: the abilityto locate and characterize medical problems; lower cost compared tomodalities such as MRI and CT; real time operation; and, the lack ofionizing radiation with the known associated health risks.

Ultrasound imaging systems transmit sound waves of very high frequency(e.g., 1 MHz to 20 MHz) into the patient's body and the echoes scatteredfrom structures in the patient's body are processed to create anddisplay images and information related to these structures.

Ultrasound imaging can be applied to various regions or organs in thebody. For example, a breast ultrasound procedure involves the placementof an ultrasound transducer over a region of interest of the breast,with the radiologist or other medical professional (the “user”) viewinga real-time ultrasound image output on a display. The ultrasound machinemonitor usually displays relevant text and/or graphical information nextto the ultrasound image for simultaneous viewing by the user. The usercan freeze a displayed image with medical findings of interest, and thecorresponding image can be printed on a printer or stored in digitalformat.

2D free hand ultrasound imaging, the most common technique used today,represents a slice through the region of interest. 3D ultrasoundscanning is available; however, it is usually used in conjunction with2D scanning techniques. Currently, most diagnostic studies are performedusing 2 D scanning technique.

The vast majority of ultrasound guided biopsies and other invasiveultrasound guided invasive procedures done by free hand and other moreautomated modes use the ultrasound machine 2D display mode. Therefore,it is desirable to have a fast and accurate way to find the targetduring such invasive procedures.

It is important to accurately store positional annotations for laterevaluation, since this is essential for final interpretation, diagnosis,and treatment. As digital storage and communication of medicalinformation replace hard copy based storage and communicationtechnologies, the accurate and consistent annotation of ultrasound andother medical images is critical. Correlation of ultrasound images withimages of the same body region obtained with other modalities (MRI, CT,mammograms, PET, etc.) becomes increasingly important for medicaldiagnostic and therapeutic purposes. As a result, precise positionalregistration of the targets is important.

This importance is illustrated by noting that finding a small tumor cansave a patient's life. The smaller the tumor is before treatment, thehigher the probability of long term patient survival or cure; however, asmall tumor is difficult to find in a patient's body and differentiatefrom other structures or artifacts in the same region. Many times asuspicious small finding can coexist in the same region with multiplebenign findings (cysts, solid benign nodules, etc.) with similarappearance, which may create confusion during a follow up exam and maylead to missing the suspicious lesion. As imaging diagnostic devicesprovide ever greater detail and sub-millimeter resolution, accurateposition registration and mapping of lesions is becoming increasinglyimportant in order to take advantage of the increased capabilities.

Ultrasound procedures are highly dependent on the device user'sexperience and training. Position recording of certain findings isimportant, especially for the small targets and/or multiple targets.Most frequently, an ultrasound user will hold the ultrasound transducerin one hand and use the other hand to operate the ultrasound machinecontrols. It is desirable to obtain the instant recording of targetcoordinates seen in the ultrasound image in relation to the anatomicalreference (for example, a nipple) and the simultaneous recording of thetransducer position. Currently, the automated recording of thetransducer position in real time scanning is limited due to the motionof the pre-selected anatomical reference secondary to body andtransducer induced motion. Therefore, it is desirable to continuouslyupdate the position of the anatomical references, or landmarks, andapply the correction to the obtained measurements.

The American College of Radiology (ACR) recommends that all ultrasoundimages be properly labeled. For example, for breast ultrasound images,the findings position, in clock face position, distance from Nipple Cand ultrasound probe position and orientation should be displayed withthe ultrasound images. Currently, ultrasound findings are manuallylabeled by an operator, which is time consuming and prone to errors.Manual labeling involves the typing of an approximate position in theorgan or part of the body, since an accurate position registration istime consuming and, importantly, difficult for the user.

A significant shortcoming in ultrasound mapping is the reproduce-abilityof target location from exam to exam. A patient's body position,including soft tissue which is subject to movement, with respect to theexamination table and position guides, and the ability to tracktransducer location in a reproducible format are limiting factors in theaccurate examination of a patient. This inaccuracy can lead toinaccurate diagnosis and, importantly, inaccurate lesion description ina comparative examination. This, in turn, leads to ambiguities in theability to definitively gauge the growth of a lesion or, critically, thesuccess of treatment.

There is need, therefore, for a sensor attachment for three dimensionalultrasound mapping that enables increased accuracy in positioning duringultrasound examination. The present invention provides such a device.

III. OBJECTS AND ADVANTAGES OF THE PRESENT INVENTION

It is an object of the present invention to significantly reduce thetime of ultrasound examination. It is a further object of the presentinvention to obtain the accurate position of selected targets inultrasound images in relation to set reproducible body reference(s) withthe corresponding ultrasound probe and patient's body position andorientation when selecting the target in the ultrasound image at thetime of examination or at a later date in the stored images withattached positional information in both 2D or 3D imaging techniques.

It is yet a further object of the present invention to eliminate orminimize errors due to inaccurate positioning and position labeling,therefore reducing the risk of costly lawsuits due to missed diagnosisand decrease the number of callbacks for the patients for repeatexamination.

It is yet a further object of the present invention to provide a sensorattaching device to enable accurate sensor placement and adherence andto, further, reduce the chance of operator error.

Among the many advantages that will be appreciated by those skilled inthe arts is that the present invention provides an easy, uniform, methodof positioning a patient for accurate examination of a target,especially with respect to follow-up or comparative examination, andcommunicating the target position among healthcare providers by guidingthe ultrasound to a previously recorded target through following thereal time display of the ultrasound transducer position in relation tothe target coordinates from a previous examination.

IV. SUMMARY OF THE INVENTION

The present invention provides an apparatus and method of use for asensor attachment for use in automated ultrasound probe positionregistration. The present invention comprises an apparatus for placementover a nipple and, optionally, a second or more sensor(s) for placementelsewhere, such as the sternum.

After initial calibration and selection of one or more body references(nipple, umbilicus, skull, etc.), positional information associated witheach individually recorded image frame or each image in a cine loop isstored with the corresponding image. Using a pointing device with thesystem display, spatial numerical coordinates of the selected pixel orregion, including the distance from the anatomical reference, depth,angle to the body axis and a graphical representation, are displayednext to the ultrasound image. Also displayed are the real time positionof the ultrasound probe and ultrasound image and target position over abody diagram or mark shown next to the real time ultrasound image,providing orientation help for the ultrasound operator. Thecorresponding body position relative to the exam table can becalculated, displayed in real time and stored with each ultrasoundimage.

Each saved ultrasound image or set of images in a cine loop can haveattached the positional information needed to calculate each pixel'sposition to selected body references, the body diagram or mark, with theultrasound probe position and orientation to selected body reference(s),the patient's body planes orientation on the exam table. All of theabove information or any combination of data can be calculated,displayed and stored. In one embodiment, the anatomical reference sensor(48) can be applied at the nipple of the breast (C) when thecorresponding breast is examined with the ultrasound machine. Other bodyparts or regions can be recorded with corresponding body referencepoints, for example: liver with umbilicus, neck with thyroid cartilageetc. Target pixel selection can be made during scanning at the time ofthe image capture, before saving the image, or at a later time at thereview station.

During future examinations, the user can be guided to the target byentering the target coordinates obtained at the previous examination,display the target in the body diagram and adjust the probe position inthe real time body diagram to overlap the target.

For the accurate automated recording of body targets and probe positionrelated to certain body references, a user continuously obtainspositional information from the selected anatomical references and theprobe positional coordinates are instantly updated.

This is achieved by continuously monitoring the selected bodyreference(s) position, which in the preferred embodiment can be achievedwith a position sensor, like a magnetic type sensor, placed next to thebody reference on the skin. In an alternate embodiment the bodyreference tracking can be obtained with an overhead tracking systemusing digital infrared or optical cameras with or without skin markers.In this embodiment, one camera can be used, or two or more cameras canbe also used to achieve a three dimensional stereoscopic effect.

The TDMD can also be used to record multiple ultrasound free hand 2Dframes in a video sequence (clip) or cine loop, with each frame savedwith the positional coordinates as described above. When using thepositional information in the multiple 2D frames of one or more videosequences corresponding to a scanned volume, the 2D images can bereconstructed in 3D volume images corresponding to the scanned region,using known 3D reconstruction algorithms. The 3D volume reconstructioncan be obtained from the original captured 2D ultrasound images or thesegmented or otherwise processed 2D images in a video sequence.

This embodiment is well suited for ultrasound breast cancer screening ordiagnostic breast ultrasound exams and can also be applied to otherregions in the body like, but not restricted, to the eye, liver,abdomen, neck, kidneys, etc. The positional tracking of the bodyreferences, including the body planes position can be combined with thepositional tracking of any type of ultrasound probes, including but notlimited to 2D and 3D hand held probes, automated 2D and 3D ultrasoundprobes.

The main role for generating and recording the positional annotationsassociated with targets in the ultrasound images is to help the targetrelocation at subsequent exams. One condition to assure accurate andreproducible positional mapping of lesions is to have reproduciblepositional mapping of the selected body references.

A sensor attaching device or part may be employed to assist in thereproducible positioning and adherence to skin of the magnetic sensors,or other type of positional sensors at body references, to reduce themapping errors due to differences at the repositioning of sensors andalso prevent the interference with the scanning procedure from thesensors connecting wire. The sensors can be of a variety of shapes,including but not limited to, a generally cup or cone shape for fittingover a nipple and a disc shape for placement at marker points such asthe sternum.

There has been outlined, rather broadly, the more important features ofthe invention in order that the detailed description thereof thatfollows may be better understood, and in order that the presentcontribution to the art may be better appreciated. There are, of course,additional features of the invention that will be described hereinafterand that will form the subject matter of the invention.

V. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an overview illustration of the inventive apparatusplaced in an ultrasound system.

FIG. 2 illustrates the functional block diagram for the inventive devicepreferred embodiment with magnetic sensors used for body references andultrasound probe tracking.

FIG. 3 depicts an alternate embodiment illustrating an overhead infraredor optical body reference tracking system.

FIG. 4 illustrates the functional block diagram for the inventive devicein the alternate embodiment with an overhead infrared or optical bodyreference tracking system.

FIG. 5 depicts the inventive apparatus in a breast ultrasoundexamination with one sensor attached at the nipple.

FIG. 6 depicts the image created during a breast examination asillustrated in FIG. 5.

FIG. 7 depicts the inventive apparatus in a breast ultrasoundexamination with one sensor attached at the nipple and one sensorattached at the sternum.

FIG. 8 shows the patient's body representation on the exam table withthe position sensors attached to the sternum, back and a breast nipple

FIG. 8A illustrates a representation of patient's planes in thereference frame of FIG. 8.

FIG. 9 illustrates the steps needed to select, measure, calculatecoordinates, display and record the positional information of theultrasound image and probe, patient's body position on the exam tableassociated with the corresponding diagnostic ultrasound images.

FIG. 10 illustrates a representative sensor nipple attachment systemwith a wireless sensor or marker and the attachment part to the skin.

FIG. 11 illustrates a representative sensor nipple attachment systemwith a wired sensor or marker and the attachment part to the skin.

FIG. 12 illustrates a representative sensor nipple attachment systemwith a wireless sensor or marker and the attachment part to the skinwith an orientation mark.

FIG. 13 illustrates another sensor nipple attachment system with awireless sensor or marker and the attachment part to the skin.

FIG. 14 illustrates another sensor nipple attachment system with awireless sensor or marker and the attachment part to the skin.

FIG. 15 illustrates a sensor nipple attachment system with a wiredsensor or marker with a detachable sensor attachment component and thehollow disc shaped attachment component to the skin, with cross hairmarks for the attachment system calibration.

FIG. 16 illustrates a sensor body attachment system for the sternum witha wired sensor or marker and the attachment part to the skin.

FIG. 17 illustrates a sensor nipple attachment system with a wiredsensor or marker with a detachable sensor attachment component and thehollow disc shaped attachment component to the skin and a soft pad forenhanced acoustic coupling

FIG. 18 depicts another hollow nipple attachment system for wirelesssensors.

FIG. 19 illustrates a sensor body attachment system for the sternum witha wired sensor or marker and the attachment part to the skin.

FIG. 20 depicts illustrates a sensor body attachment system for thesternum with a wireless sensor or marker and the attachment part to theskin.

FIG. 21 shows the steps needed for the sensor attachment systemcalibration.

FIG. 22 shows the steps needed a different sensor attachment systemcalibration using a cube shape.

FIG. 23 shows the steps needed a different sensor attachment systemcalibration using a cube shape.

FIG. 24 describes the steps needed for the positional registration ofthe patient's body on the exam table or first set of images and a priorsecond set of images with the body planes calculated with the skinsensors and images position data.

VI. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Before explaining the preferred embodiment of the present invention indetail, it is to be understood that the present invention is not limitedin its application to the details of arrangements of the components setforth in the following description. As will be appreciated by thoseskilled in the arts, the present invention is capable of otherembodiments and of being practiced and carried out in various ways.Also, it is to be understood that the phraseology and terminologyemployed herein are for the purpose of description and should not beregarded as limiting. It is also to be understood that where ranges areprovided for various aspects of the invention and for examples, they areapproximate ranges and are not to be limiting except where notedotherwise.

Turning to FIG. 1, an over view of the physical aspects of an ultrasounddevice employing the inventive apparatus 20 is seen. Ultrasound machine22 is a standard device including display 24, interface with keyboard 26and pointer 28, chassis containing operating hardware (not seen) 30,probe connecting cord 32, and probe 34.

Inventive apparatus (also referred to as three dimensional mappingdisplay, or TDMD) 20 is depicted and comprises TDMD display 38, TDMDChassis 40 containing hardware (also referred to as a “processor”) andsoftware (not seen; described in detail below), 3D magnetic trackingmember 42 with the transmitter 44 connected to TDMD 20 by 3D magnetictracking member cord 46, first magnetic sensor 48 connected to TDMD 20by first magnetic sensor cord 54 and second magnetic sensor 52 connectedto TDMD 20 by second magnetic sensor cord 56. A 3^(rd) and 4th positionsensors, 49, 51 can be attached to track the patient's body position inreference to the exam table (FIG. 7, 8). The position sensors may alsobe of a wireless variety, thus sensor cords 56, 58 would not berequired. Also a combination of wired and wireless position sensors canbe used to provide the position tracking module with positionalinformation from the tracked anatomical references and the ultrasoundprobe or probes. (For completeness in explaining FIG. 1, Patient A issituated on examining table B.)

Turning to FIG. 2, a block diagram illustrating the various generalworking aspects of inventive device 20 are shown. All or any of the bodyreference magnetic sensors 48, 49, 51 and the ultrasound probe magneticsensor 52 provide the positional information to the TDMD 20 3D positionhoard/module 60 (not seen). Video output 24 from ultrasound device 22 isdigitized by the dedicated TDMD module/board 40. It should be noted thatthe analog to digital image conversion may not be needed if theultrasound machine can be interfaced and it can directly provide thedigital images to the TDMD 22.

TDMD can continuously track one or several body reference markers, whichcan increase the overall accuracy of the system. If multiple attachedpositional body markers or sensors are used, all of them or only some ofthem can be continuously or intermittently tracked.

To ensure reproducible and accurate mapping of the ultrasound images,magnetic sensors 48, 49 and 51 should be attached at well-defined andreproducible sites, outside or inside the body, during repeatedultrasound exams. Magnetic sensors 48, 49, 51 and 52 may be usedsimultaneously or singularly. It should also be noted that the TDMDcould accommodate additional positional sensors as well.

As a non-limiting example, in the case of a breast ultrasound exam, toobtain reproducible mapping results, the magnetic or other positionsensors should be attached to the Nipple C and monitor the position ofthe same point at the nipple, for example, the nipple center at the skinlevel, during repeated ultrasound exams. For instance, the center of theNipple C top surface D can be the point of attachment for the anatomicalreference position sensor (FIG. 10). It is desirable to have themagnetic sensor wire 54 outside the region of interest to be scanned.Continuing with the breast ultrasound exam example and with a magneticsensor at the Nipple C, if magnetic sensor wire 54 is aligned in adirection perpendicular to the breast's coronal plane or a transverseplane through the nipple, the entire breast surface may be available forscanning, without the magnetic sensor wire in the path of the ultrasoundprobe 34.

To address the above, a sensor attachment device 92 may be employed toaid the attachment of a wired or wireless position sensor to the NippleC. Sensor attaching device 92 can be built as a disposable part or as areusable part after sterilization.

In one preferred embodiment, sensor attaching device 92 may be shapedlike a cup covering the Nipple C or any other similar shape covering theNipple C. The sensor attaching device can be applied over the Nipple Cand firmly attached to the Nipple C or areola skin with a skincompatible adhesive or tape. Turning to FIG. 10, magnetic sensor 48 isfirmly attached at the top of nipple cover 92 For the wired sensors, inFIG. 11, a thin firm or flexible stick or tube 96 can be attached to thetop 98 of the cover 92 and the wire 54 is attached to or included in thethin stick or tube 96, to hold the wire relatively perpendicular to thebreast coronal plane and prevent obstruction of the ultrasound probe 34path over the breast skin.

In an alternate embodiment, sensor attaching device 92 includesorientation markers 102 which enable positioning of the sensorattachment device with the markers having the same orientation duringrepeated exams, (FIG. 12). As depicted in FIG. 12, optical or infraredreflector(s) or emitter(s) are used to track the nipple C positioninstead of a magnetic sensor, 48, and is attached to the upper surface104 of sensor attaching device 92 for the use with overhead optical orinfrared cameras embodiments of the invention, FIG. 3. The protrudingstick or firm tube 96 can be attached to the top or on the side of thecover 98 for the wired magnetic sensor 48

In yet another embodiment, and as depicted in FIG. 13, a hollow disc 106is applied around the entire Nipple C or any part thereof and sensorattaching device 92 can then be applied to hollow adhesive disk 106instead of directly to the skin. The sensor 48 with the nipple cover 92can be attached to the adhesive disc directly, as depicted in FIG. 14.The hollow disc can be made from flexible tape when the nipple cover isattached to it (FIG. 14) or it can be made from a hard material when thesensor 48 is directly attached to it or to a protrusion above the disc(FIG. 15). For optical or infrared markers, the marker or markers can beapplied above the nipple as shown in FIG. 18. All attachment deviceparts can be made from ultrasound transparent materials, to allow for acomplete evaluation of the periareolar and retroareolar regions. Thenipple attachment part can have a sensor attachment component and anipple attachment component. The detachable component with thepositional sensor can be made from a non-ultrasound transparent material(FIG. 15).

For better acoustic coupling, to obtain good quality images of theretroareolar region, the part attached to the body skin can be coveredor embedded in an ultrasound transmitting soft pad (FIG. 17). Any of theabove described embodiments can have the soft pad attached to them.

All sensor or marker attachment embodiments can be attached to the skinwith an adhesive material or using adhesive tape to cover the attachmentpart and adjacent skin. The adhesive material or tape can be ultrasoundtransparent, like Tegaderm™ (3M Corporation, St. Paul, Minn., USA) toprevent the interference with ultrasound images acquisition.

For practical use it would be difficult to have the AR tracking sensorin the nipple attachment piece positioned exactly at the center of thenipple, every time a patient is scanned. To address this limitation, thenipple attachment piece with the sensor (48) can be calibrated to trackthe nipple center point position in the 3D reference frame. In thisconfiguration, the skin attachment part with the position sensor mountedon it and off the center of the nipple C, can be calibrated to monitorthe Nipple C center position. For example, the center of the skinattachment part 15 hollow disc would match the nipple C center.

Such calibration of the skin attachment part can be performed using anymethod to perform a point or stylus 3D calibration in a referencesystem. For example, the nipple attachment component is fitted with acrosshair over the inner ring, with the cross point corresponding to theinner ring center which can be fitted over the nipple (99 in FIG. 15)and using the flowchart in FIG. 21. Such a calibration can also beperformed using a solid cube as in FIG. 22 following the flowchart inFIG. 23. It is also understood that any combination of the aboveembodiments is possible and is part of the presented inventionteachings.

During an ultrasound exam, the patient's body position and orientationto the exam table or other fixed reference can change, which can have aneffect on the position of the body internal structures when referencedto other body landmarks in a spatial frame and therefore have an effecton the measurement and description of a lesion's position. During thereal time ultrasound exam image acquisition and capture, each internalultrasound target position relative to the body references depends,among other factors, on the patient's position relative to the directionof the gravity force or the earth's magnetic field. Therefore thepositional relation between the patient's body position and anexamination table, B or other reproducible fixed reference used toposition the patient, a chair or a wall for example, can be associatedwith the ultrasound images or other images of the body to aidrepositioning the patient at subsequent imaging and match the gravityforce effect between temporally distinct image sets. The gravity forceeffect is larger on deformable structures, like the breast. For example,during a breast ultrasound exam, the position of a small target in thebreast relative to the nipple or other anatomical reference can changebetween the supine and half decubitus patient positions on theexamination table. Unlike the approaches of the prior art, at the followup exams or during the same patient exam, the patient whole bodyposition can be adjusted to match the body position relative to theexamination table or other known fixed reference object recorded withthe previously obtained ultrasound images and match the position ofinternal targets referenced to body landmarks in previous images,therefore help finding a target with the previously recorded coordinatesrelative to selected body landmarks.

To monitor the patient's body axes and planes in reference to an examtable, the body reference position sensor angles can be dynamicallyrecorded and the values used to calculate the patient's body positionrelated to the exam table (FIG. 9). However, to assure the body positionto the exam table reproducibility at subsequent exams, the positionsensor(s) tracking the body position would need to be reattached to thebody in the same position referenced to the body, as they were at thefirst exam. This is a challenging task since small angular differencesin the sensors position on the body can generate significant changes inpatient's planes and axes orientation and generate registration errors.For example a position sensor attached to the nipple could not be usedto monitor changes in the patient's body position due to the breast'sdeformable nature and sensor position changes due to the ultrasoundprobe induced deformation, unrelated to the body position. To addressthe above, a different sensor, 49 and sensor attachment part can beused. The position sensor(s) can be firmly attached to a sensorattachment part which is calibrated to the sensor and designed to beeasily repositioned in same position and orientation at the patient'sbody. In one embodiment, the attachment part for the body positionsensor(s) is designed as a long profile with a curved end which can beplaced and aligned with the sternum long axis with the curved end at thesternal notch or the xiphoid process of sternum. For example a magneticsensor 49 can be attached to the sternum attachment part (FIG. 19).

In a different embodiment, dedicated markers can be used for optical orinfrared position tracking (FIG. 20).

The sternum attachment can be calibrated to the attached positionsensor(s), for example it can have the long axis or the attachmentpart's flat plane calibrated to the sensor. One or more points at theattachment part with the position sensor can be calibrated using themethod explained in FIG. 21, 22, 23 or any other calibration method canbe used. The calibrated body attachment part can be used to define linesor planes which can be aligned with the body planes and axes, tofacilitate the attachment part reposition on the body. Once attached tothe sternum skin, the calibrated attachment part and sensor can trackthe patient's body long axes and planes.

The sternum attachment part rotation around the long axis duringpatient's movement can induce errors in the body position tracking. Toaddress this limitation, in a different embodiment, a different, fourthposition sensor 51 (FIG. 8) can be attached at a reproducible positionat the patient's body, for example the skin on the back, over aprominent spinous process of a cervical or thoracic vertebra. The examtable or other reference object can move during the examination, tocompensate for the table motion during the patient's exam, a positionsensor 53 (FIG. 8) can be attached to the table and any table positionchange in the position reference frame can be calculated from the sensor53 output and applied to the other positional calculations for the bodyand ultrasound probe position and orientation. The table positionmonitoring is not needed when the spatial reference frame, the magnetictransmitter for example, is firmly attached to the exam table and wouldfollow the table movement. The plane generated by the data processedfrom the calibrated sternal attachment part and sensor and the positionsensor attached at a different body location, like at the back of thebody over the spinous process of a vertebra will define a referenceplane S, which is the sagittal plane in the used example. The referenceplane S and sensors position can be tracked during the patient's examand dynamically displayed with alpha numerical coordinates and graphicalover the body diagram, mark or other body or body part representationFIG. 8.

In yet another embodiment, the position of a second reference used inaddition to the sternum sensor, like a vertebral spinous process, can bemeasured at one or several times during the exam with a position sensorattached to a calibrated object. An example is the calibrated ultrasoundprobe with a position sensor, by touching the skin over the selectedlandmark with a preset point of the calibrated object, like ultrasoundprobe scan surface center or margin. The reference plane of the body isrecalculated at each measurement, in the example with the spinousprocess of a vertebra; the sagittal plane of the body position isrecalculated at each repeat measurement.

In another embodiment, the position of a body reference, like thespinous process tip of a vertebra can be calculated from ultrasoundimages of the selected body reference. With the calibrated ultrasoundprobe, the selected body reference is scanned and single frames orsequential frames in a video clip can be obtained. The body referencepixels are selected in one or more images and the spatial coordinates ofthe selected pixels are calculated in the reference frame with theposition data from the sensor attached to the ultrasound probe. The bodyreference pixel selection in the ultrasound images can be manual, bypointing to the pixels, semi-automatic or fully automatic with imageprocessing algorithms dedicated for image analysis. To facilitate theimaging of superficial structures like the tips of a spinous process ofa vertebra, tip of acromio-clavicular joint, xiphoid process of sternumor any other structure, a standoff pad with an ultrasound transmittingmedium can be used.

In yet another embodiment, the sternum attachment part and sensorposition relative to the body can be stabilized with two extensions 120,attached to the clavicles (FIG. 16). The extensions 120 ends can betaped at the clavicle and opposite ends firmly attached at the sternumattachment piece 118 or attached to a pin which allows the extensions torotate to fit the overlaying with the clavicle bone in a range ofanatomical variants (FIG. 16). The described methods to track a bodyposition to a fixed reference can be performed alone or combined, alsowith one or more sensor(s) attached to any part of the body.

With the positional data from the sensors attached to the body, thepatient's body axes and planes can be calculated dynamically inreference to the exam table or other 3D reference system. With onepatient body plane defined in a positional reference system, otherplanes can be calculated and used to generate positional coordinates.For example, once the sagittal plane of a patient's body is determinedand tracked, the coronal plane can be calculated and used for the clockface position coordinate calculation and display in a breast ultrasoundexam. The position of a body diagram or other second set of previousimages representing the body, with or without a first set of real timeultrasound images, referenced to the exam table, can be calculated usingthe body reference sensors output, also displayed and stored on demand(FIG. 8).

The calculated patient's planes can be used to align the patient's bodyand ultrasound images during an ultrasound exam with one or more sets ofprevious images, for position registration purposes. The previous setsof images may be represented by 2D or 3D body marks or diagrams ormedical images like MRI, CT etc. The body landmarks tracked with thesensors and the corresponding attachment parts can be identified inother sets of images and the position registration between the differentsets of images can be performed. For example the sternal notch,clavicles and spinous processes of vertebrae can be easily identified inCT scan or MRI images, corresponding body planes can be calculated andaligned in the ultrasound set of images and the other sets of images,previously acquired.

Furthermore, when in a patient the same one or more body planes aredefined in the first set of ultrasound images and in a different priorset (s) of images, by using same or different body landmarks as in thefirst set of images, the body position registration during theultrasound exam can performed by aligning the known similar bodyplane(s) or axis(es) in the different sets of images, followed by theshift of the entire body volume of one image set to match one or morecommon body landmark points (FIG. 24).

Alternatively, any two different sets of images of the body with knownsimilar orientation planes can be coregistered by aligning the planesand axes followed by shifting the entire aligned volume to one or morecommon body landmark points.

The advantage of this method of registration for different image sets isthat it eliminates the need for multiple fiducial markers and allows theregistration of body volumes when using different anatomical landmarksto define the body planes and axes position and orientation in space.

Other configurations will work as well. For non-limiting example, FIG. 3illustrates an alternate configuration in which second sensor 52, whichcan be optical, magnetic or any other type, provides the positionalinformation associated with ultrasound probe 34 to the TDMD 3D positionboard/module 60. The overhead infrared or optical anatomical reference(AR) tracking system 43 provides the positional information to the TDMDcomputer 40. Video output 24 from the ultrasound device 22 is digitizedby the dedicated TDMD module/board 40. Again, analog to digital imageconversion is not required if the ultrasound device 22 can be interfacedand directly provide the digital images to TDMD computer 40. The digitalultrasound images with the associated positional information aredisplayed in the TDMD computer display 38 or stored for review andprocessing at a later time.

Turning to FIG. 4, a block diagram illustrating the various generalworking aspects of inventive device 20 are shown. Second position sensor52 attached to the ultrasound probe provides the positional informationto the TDMD 20 3D position board/module 60 and overhead infraredposition detector 43 transmits positional information to TDMD computer40. Video output 24 from ultrasound device 22 is digitized by thededicated TDMD module/board 40. It should be noted that the analog todigital image conversion is not needed if the ultrasound machine can beinterfaced and it can directly provide the digital images to the TDMD22. Also, and as will be appreciated by those skilled in the arts,sensor types can be mixed without interfering with the function of theinvention and are meant to be included within the spirit and scope ofthe present invention.

Returning to FIG. 1, second position sensor 52 is attached to theexterior of probe 34 and, as seen in more detail in FIG. 5, firstmagnetic sensor 48 is positioned at the body reference, here, the breastnipple C of Patient A.

Ultrasound device 22 video output 24 is directed to TDMD video captureboard at TMDS Chassis 40 through video output cord 58 as is 3D magnetictracking member 42 through 3D magnetic tracking member cord 46. TDMSdisplay 38 is then enabled to shows images D generated by ultrasounddevice 22 and associated positional data as collected from 3D trackingmember 42, first sensor 48 and second position sensor 52.

Turning to FIG. 5, a detailed view of probe 34 with the second positionsensor 52 and first position sensor 48 applied at the right Nipple C.First position sensor 48 continuously tracks the body referenceposition, the Nipple C in this case, to compensate for motionregistration errors during the ultrasound exam. FIG. 6 illustrates TDMDdisplay 38 with the captured video image D from the ultrasound machineand the body diagram of FIG. 5 with the probe 34 position andorientation at the time of image capture D and two different targets Fand G in body part diagram I, and F′ and G′ as selected in image D imagecapture.

Additionally, each target is displayed with the associated position(clock face position or degrees to longitudinal axis and anatomicalreference as center) and distance (cm) from the selected anatomicalreference F and G. Positional coordinates are displayed under body partdiagram I in FIG. 6. While the inventive device enable any number ofcoordinates to be displayed, here the example includes Target number(T), example F and G, Positional in reference to anatomical reference inhour format (here, 9:30 for F and 9:00 for G), position from anatomicalreference point in degrees (here, 15° for F and 0° for G), and distancefrom anatomical reference point in centimeters (cm) (here, 10.5 cm for Fand 7.41 cm for G). Also, probe 34 position location is identified attransducer position Icon E.

Additionally, an additional display function is to show a cumulativearea of the transducer positions (via icon E) over the body diagram,where the ultrasound images were recorded during patient examination.This will allow for the quick evaluation of ultrasound examinationcompleteness, at the time of the examination or at a later time.

In the preferred embodiment, any off the shelf generic PC computer withWindows XP®, Windows 7 (by Microsoft Corporation, Redmond, Wash.) can beused to run instructions compiled in C++ and dotnet languages. Whilepreferred, those skilled in the arts will understand that the inventioncan be implemented on any other computer platform and operating system.

The software to run the program is that incorporated by reference above.The software substantially used to process the data received by theprocessor form the at least one sensor and data from the ultrasound tomanipulate the data for identifying, and storing in memory as selectedby the user, target site location and size information in relation toselected anatomical reference points for simultaneous review andinterpretation and later retrieval for comparative purposes with laterexamination, whether compared in real time or a later time based uponsaved data. The inventive device enabling a user to accurately review,evaluate, and compare examination results by having anatomical referencepoint guides to isolate target sites.

The body diagram representation is not limited to the “bird's eye view”type like the “clock” representation for the breast, but more complexand realistic three dimensional representations of the body or bodyregions, including images obtained with other modalities like MRI,mammograms, gamma cameras or positron emission tomography and usingcontour rendering algorithms, can be used. The calculated and recordedpositional data can be displayed in these representations. Theultrasound transducer position, orientation, can be depicted in arealistic appearance in space so it can be easily reproduced atsubsequent examinations.

Additionally, the preferred 3D position registration system is based onmagnetic tracking technology (for example, like that manufactured byAscension Technology, Burlington, Vt.); however, any other suitabletechnology, such as optical or ultrasound, may be employed. Moreover,the inventive device can be deployed as an add-on to any existingultrasound unit, and can outfit DICOM compatible and non-DICOM machinesas well. The infrared sensors, also commercially available (NaturalPoint Inc, Corvallis, Oreg.), comprise at least one infrared cameraswith the dedicated hardware and software receiving reflected infraredlight from the reflectors or emitted infrared light from small infraredlight sources applied over the anatomical references. The infraredcameras can be replaced with optical cameras and the infrared reflectorswith optical markers. One or more infrared or optical cameras can alsobe used.

The ultrasound probe and anatomical reference point real time trackingis not limited to the above solution, but other tracking modalities likeultrasound, optical, inertial etc. can be used for the ultrasound probeand optical/pattern recognition, magnetic, etc. for the anatomicalreference point real time tracking. It should also be noted thattracking modalities can be used in combination with one another, fornon-limiting example, ultrasound tracking with optical tracking. It isalso notable that the described TDMD system and method can optionally beused with the anatomical reference tracking feature disabled.

In any of the above configurations, initial calibration is needed toregister the ultrasound probe scanning plane orientation and position.Any 3D calibration method for 2D ultrasound probes, as available in thepublished literature can be used.

The preceding merely illustrates the principles of the invention. Itwill be appreciated that those skilled, in the art will be able todevise various arrangements which, although not explicitly described orshown herein, embody the principles of the invention and are includedwithin its spirit and scope. Furthermore, all examples and conditionallanguage recited herein are principally intended to aid the reader inunderstanding the principles of the invention and the conceptscontributed by the inventors to furthering the art, and are to beconstrued as being without limitation to such specifically recitedexamples and conditions. Moreover, all statements herein recitingprinciples, aspects, and aspects of the invention as well as specificexamples thereof, are intended to encompass both structural andfunctional equivalents thereof. Additionally, it is intended that suchequivalents include both currently known equivalents and equivalentsdeveloped in the future, i.e., any elements developed that perform thesame function, regardless of structure. The scope of the presentinvention, therefore, is not intended to be limited to the exemplaryaspects shown and described herein. Rather, the scope and spirit ofpresent invention is embodied by the appended claims.

1. A system for a position sensor comprising: an attachment member forplacement over the breast nipple, the attachment member configured forattachment to the areola or nipple skin; a protruding member attached tothe attachment member; and a position sensor attached to the attachmentmember or the protrusion component.
 2. The system of claim 1 wherein theattachment member configuration is selected from the group of cup-like,cone, and disc shapes.
 3. The system of claim 1 wherein the positionsensor is attached to a detachable component, the detachable componentenabling firm attachment to the skin of the nipple or areola.
 4. Thesystem of claim 1 wherein the attachment member and protruding memberare calibrated to the attached position sensor.
 5. The system of claim 1wherein the position sensor is attached to the areola or nipple skinwith an adhesive.
 6. The attachment member of claim 1 selected from thegroup of cup-like, cone, and disc shapes.
 7. The system of claim 1further comprising a wired body position tracking sensor comprising anelongated component with a curved end configured to fit the sternalnotch or xiphoid process.
 8. The system of claim 7 further comprising alinear extension connected to the elongated component on each side atone end and attached to the clavicle on the same side at the other end,and a wired position sensor attached to the sternum component.
 9. Thesystem of claim 1 further comprising a wireless body position trackingsensor comprising an elongated component with a curved end configured tofit the sternal notch or xiphoid process.
 10. The system of claim 9further comprising a linear extension connected to the elongatedcomponent on each side at one end and attached to the clavicle on thesame side at the other end, and a wired position sensor attached to thesternum component.
 11. A method to calculate the patient's body planescomprising the steps of: attaching a sternum attachment system withattached sensor and data output to the sternum; measuring the positionof a posterior body landmark; and, calculating a reference plane. 12.The method of claim 11 wherein the sternum attachment system is wired orwireless.
 13. A method to register the body volume in a patient and aprevious set of images comprising the steps of: calculating thepatient's body planes using a sternum attachment system with attachedsensor and data output; measuring the position of a posterior bodylandmark; calculating a reference plane; and, aligning the body volumeby the reference plane and translate the volumes to one or more commonpoints.
 14. The method of claim 31 wherein the sternum attachment systemis wired or wireless.
 15. The system of claim 1 wherein the positionsensor comprises a wireless sensor.
 16. The system of claim 1 whereinthe position sensor comprises a wired sensor.